The use of a Global Positioning System (GPS) satellite constellation for obtaining a terrestrial position fix (latitude, longitude, and altitude) is widespread and well known. It has been proposed that mobile terminals (such as, but not limited to, cellular telephones, personal digital assistants, etc.) in modern wireless telecommunications systems include a capability to receive GPS signals and calculate position on the surface of the Earth.
In an indoor environment, GPS signals from the GPS satellites are weak. For implementing precise positioning indoors, GPS enabled devices require not only a higher level of sensitivity but also assistant information, such as Time Doppler shift, Broadcasting Ephemeris, and Almanac for quick positioning information. The assistant information is transmitted as Assisted GPS (AGPS) information. However, mobile networks do not support AGPS in some areas.